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UC Berkeley: CalSol
The CalSol solar car team is a fully student run team at the University of California, Berkeley. CalSol's first race was in SunRayce 93. CalSol placed 3rd overall in SunRayce 97, and 1st in class in FSGP 2003. CalSol's most recent race was FSGP 2009, and plans to compete in the World Solar Challenge 2011. Technology BRAIN ''' Due to difficulty in assembling and testing a reliable electrical system for the previous car, CalSol rethought the electrical system with a focus on modularity. Each electrical board on the car uses a standard BRAIN module, similar to an Arduino Nano with built-in CAN support. Once prototyped, these boards were purchased in bulk and professionally fabricated. This allowed an interchangable central unit for each board that we could fall back on and greatly simplified the rest of our board design. Using through hole components on the "skeleton" boards the brains plug into also allowed for easier replacement of parts. BRAIN blog post Open Source Designs Cars '''Impulse Although similar at first glance to GoldRush, the latest car is a fully reimagined design. It features a focus on improved aerodynamics, a chassis designed to redirect force away from the driver, and the latest SunPower C50 cells. The electrical system focuses on modularity by using the team's custom CAN-enabled "BRAIN" microcontrollers for each node. Following stability issues with the NGM motor controllers, the new car has switched to the Tritium motor controller. This car is slated to complete in time for the WSC 2011. Gold Rush ' CalSol's first car with regulation required upright seating and a traditional steering wheel (Cars previous to NASC 2008 generally where driven lying down to improve aerodynamic performance). The need for upright seating made the team revert to a 3-wheel design, with the driver sitting in the rear fairing. The shell is made of Kevlar and Nomex honeycomb, with a Chromoly Steel Chassis. The car also featured a unique suspension design. Loss in team continuity following several missed and cancelled races resulted in a team "reboot" during the construction of Gold Rush. This unfortunately led to an electrical system which was poorly understood by the new members and unable to be fully operational by race-time. Gold Rush served mostly as a learning experience, competing only in the 2009 FSGP. However the lessons were well learned, and in the aftermath the team is now probably at it's healthiest ever. '''Beam Machine ' Based off of the same shell design as the Solar Bear, the Beam Machine featured a narrower profile, an aluminum chassis and double A-arm suspension. It also featured an innovative battery protection system and earned the Best Stock Array award. This was CalSol's last 4-wheeled design and the first to use 20% efficient SunPower a300 cells encapsulated by SunCat Solar. '''Solar Bear The first car built after the split with the Stanford Team, it used little from the previous cars designs. The car used a Chromoly steel chassis, and was designed to be a rugged, sturdy vehicle. It was first in class in FSGP 2003. Third Degree Burner The Third Degree Burner was built using the upper shell of the previous vehicle, the Afterburner II, redesigned to accomidate a new SunRayce rule requiring 4 wheels. The chassis, suspension, drive train, electrical systems, and telemetry were all rebuilt. The chassis is a carbon-honeycomb box structure. The suspension combines Risse Racing Technology shocks with custom-designed aluminum members. The aerodynamic shell is molded from kevlar and epoxy, in order to be light and rigid while providing a safe, energy-absorbent structure around the driver. The solar cells are made by ASE America and are 14.5 % efficient. They are split up into modules of 4x7 cells on average, each module being entirely sealed inside a rigid resin and glass matrix. The electrical system combines New Generation Motor Corp's hub motor with GB Battery's Nickel-Metal-Hydride cells, along with the solar array and some accessories (turn signals, horn, telemetry, etc.). The Third Degree Burner's only major event was SunRayce '99, a 1400 mile race. 'Afterburner II ' The Afterburner II is the Third Degree Burner's immediate predecessor, built as a joint venture between UC Berkeley and Stanford. It has upwards of 8,000 miles on it. It uses an 8-hp Solectria motor gives the vehicle zippy acceleration while providing good efficiency (~90% at cruising speeds of around 50 mph), and claims a top speed of 74 mph. 'California Dreamin' ' CALSOL's first solar vehicle, California Dreamin', was built by team members between the summers of 1990 and 1993. It first raced in SunRayce 93.